my fiance has taught/practiced/etc MMA for quite a few years now and about 6 months ago i started messing around with him. it's an AWESOME work out to relieve stress and tone your body! not only are there so many different aspects and moves to learn that your body works new muscles constantly, but it's not too bad to roll around with your hunk 
possible new years resolution for someone that has done the whole weight loss thing successfully, but now needs to gain some muscle. good luck!